Democrats expressed alarm and outrage after House Speaker Kevin McCarthy, R-Calif., gave Fox News host Tucker Carlson access to thousands of hours of surveillance footage from the Jan. 6, 2021, insurrection at the U.S. Capitol.

Senate Majority Leader Chuck Schumer, D-N.Y., said that the release of the footage “poses grave security risks to members of Congress and everyone who works on Capitol Hill.”

“The speaker is needlessly exposing the Capitol complex to one of the worst security risks since 9/11,” Schumer wrote in a letter to colleagues. “The footage Speaker McCarthy is making available to Fox News is a treasure trove of closely held information about how the Capitol complex is protected and its public release would compromise the safety of the Legislative Branch and allow those who want to commit another attack to learn how Congress is safeguarded."

House Democratic leader Hakeem Jeffries, Schumer’s fellow New Yorker and lower chamber counterpart, agreed with his sentiment.

“The apparent transfer of video footage represents an egregious security breach that endangers the hardworking women and men of the United States Capitol Police,” Jeffries wrote to his colleagues.

Carlson said his team is spending the week at the Capitol poring through the video and preparing to reveal their findings to his viewers. But granting exclusive access to sensitive Jan. 6 security footage to such a deeply partisan figure is a highly unusual move, seen by some critics as essentially outsourcing House oversight to a TV personality who has promoted conspiracy theories about the attack.

Many critics warn that Capitol security could be endangered if Carlson airs security footage that details how the rioters accessed the building and the routes lawmakers used to flee to safety. And a sharply partisan retelling of the Capitol attack could accelerate a dangerous rewriting of the history of what happened Jan. 6, when Trump encouraged a mob of supporters to head to the Capitol to overturn Joe Biden’s election.

“It is not lost on anyone that the one person that the speaker decides to give hours and hours of sensitive secret surveillance footage is the person who peddled a bogus documentary trying to debunk responsibility for the Jan. 6 riot from Donald Trump onto others,” said New York Rep. Dan Goldman, who served as counsel during both of former President Donald Trump’s impeachment trials before his election to Congress.

“Kevin McCarthy has turned over the security of the Capitol to Tucker Carlson and that’s a scary thought,” Goldman said.

Schumer wrote that “giving someone as disingenuous as Tucker Carlson exclusive access” to the footage “is a grave mistake by Speaker McCarthy.”

Mississippi Rep. Bennie Thompson, who chaired the House Select Committee investigating the Jan. 6 attack, told NPR that the release of the video footage could be “dangerous.”

“It’s dangerous because some of the video we chose not to share, in concert with the Capitol Police, because it would compromise the security of the Capitol,” Thompson said, describing a “rigorous process” of reviewing the footage to make sure that it would not make the complex less secure.

“There were things that we did not show, but it was because the Capitol Police said ‘no, this is a security risk, don’t do it,’” he said.

Thompson suggested that the footage could reveal the “secured path” that Members of Congress were escorted through at the height of the insurrection, which is “not known to the public.”

“It’s available on the video,” Thompson told NPR. “So if there was someone who wanted to do harm to people, then access to this video, clearly, puts those individuals who work in that building, who visit that building, at risk.

California Rep. Zoe Lofgren, who served on the panel with Thompson, agreed.

“It’s really a road map to people who might want to attack the Capitol again,” she said. “It would be of huge assistance to them.”

News that McCarthy was turning over the footage to the far-right news personality was first reported by Axios. McCarthy told The New York Times on Wednesday that he was fulfilling a promise by releasing the footage.

“I promised,” McCarthy told the outlet. “I was asked in the press about these tapes, and I said they do belong to the American public. I think sunshine lets everybody make their own judgment.”

McCarthy also sent a fundraising email to supporters about the Jan. 6 footage, according to The Washington Post, saying it was “in the public interest” to release the footage, attacking the House Select Committee’s investigation as “partisan.”

“Patriot, you deserve the facts — all of the facts,” the email reads. “I promised I would give you the truth regarding January 6th, and now I am delivering. I have released the full 44,000 hours of uncut camera surveillance footage.”

When asked if Carlson might argue that the Jan. 6 panel selectively editing the footage, Thompson dismissed the notion.

“There’s absolutely nothing that we produced that we can’t prove,” the Mississippi Democrat told NPR. “The only items that we did not share with the public … was because of the Capitol Police’s insistence that we not do it because it would make the Capitol more vulnerable.”

“Speaker McCarthy ought to understand the gravity of what this decision means to the public,” he added.

“To make the entire 44,000 hours of video available to just one network is not in the good interests of this country,” Thompson warned.

The Associated Press contributed to this report.